Ultrasonic machining devices usually comprise a vibration exciter, for example, a piezoelectric vibration exciter, a coaxial sonotrode, and a tool that is also coaxial. The sonotrode is a rotationally symmetrical body and acts as a spring-mass system. By means of the vibration exciter the sonotrode is excited to longitudinal autooscillators, which form around a nodal surface. Frequently the sonotrode has on the input side a larger cross section than on the output side. Thus, it acts as an amplitude intensifier.
The known ultrasonic devices are relatively long in the axial direction of vibration, so that workpieces that are difficult to access are often hard to machine.